1. Field of the Invention
The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus such as an interchangeable-lens camera in which a lens unit is removable from a camera body.
2. Description of the Related Art
Conventionally, interchangeable-lens cameras which allow a lens unit to be removed from a camera body for replacement is known in the field of film cameras. Recently, cameras which allow lens units to be changed have been proposed in the field of digital cameras as in the case of film cameras.
Generally, in such interchangeable-lens cameras, a lens unit is attached to the camera body using a bayonet mount. That is, the lens unit is mounted on the camera body by turning the lens unit on an optical axis with respect to the camera body.
Incidentally, some digital cameras have an image pickup element such as a CCD incorporated in the lens unit (see, for example, Japanese Patent Application Laid-Open No. 2004-350047). In such digital cameras, however, if the lens unit is attached to the camera body using a bayonet mount, it is not possible to provide a sufficient number of electrical contacts.
To deal with this problem, Japanese Patent Application Laid-Open No. 2003-156790 proposes an interchangeable-lens camera in which engaging members and fastening members of the lens unit and camera body are installed on opposite sides of the optical axis. In this camera, the lens unit is engaged with the camera body via the engaging members, tilted toward the camera body, and then fastened to the camera body via the fastening members. This makes it possible to mount the lens unit on the camera body without rotating it on the optical axis.
However, with the camera described in Japanese Patent Application Laid-Open No. 2003-156790, when mounting the lens unit on the camera body, an operator must hold the lens unit and camera body in different hands, having both hands full and interrupting other operations.